At the magazine, building a Jeep inline 4.0L six with a 4.2L crankshaft (stroker motor) is very popular. Tony Hewes (Hewes Performance, Reno, Nevada) and I did a series of HD videos and shared our favorite components for a 4.6L (0.030" overbore with the 4.2L crankshaft) stroker motor build for combined street and trail use.

Since then, we have received a lot of feedback and continue to address the tuning and camshaft requirements of these engines. From our testing, the pre-coil pack (1998 TJ and older 4.0L) engines with older style injectors do very well with Ford 5.0L V-8 24-pound injectors—no emission quirks, "Engine Check" lights or other issues when tuned correctly. Ford part number F1TE-D5A or Bosch number 280 150 947 is the specific injector type. These engines work well with the 252H CompCams grind camshaft and 8.7:1 compression.Later, 1999-up TJ Wrangler and 2000-2001 Cherokee engines with coil-pack ignition have square injector connector plugs. For these engines, stroker builders use the Dodge Ram 5.9L V-8 injectors listed for 2000-up with coil pack. This is the injector that HESCO calls a "24-pound/hour”. HESCO supplies rebuilt GB injectors, although new Mopar OEM part numbers are available. This injector also crosses over to the aftermarket Bosch Fuel Injector #62005 offered at Summit Racing for a significant price per injector.

Here is the GB website: http://www.gbreman.com/index.html. The 5.9L Ram truck V-8 application is the GB812-12132 injectors for engines to 2003.I researched further and came up with the OEM 5.9L Mopar V-8 injector part number: 53031740AA. (I used 2001 as a clear year for coil-pack and square injector plug.) This OEM Mopar injector is 23.61 pound/hour rated at 43.5 PSI. This is a "high impedance" injector design with a square plug socket.

The OEM injector on a coil-pack engine rates 22.5 pounds/hour at 49.0 PSI fuel pressure, which may work okay on a coil pack stroker engine unless the cylinder head, compression or camshaft/head combination is an issue for the PCM. Fuel rail pressure of 49.2 +/- 2 PSI should be confirmed by factory testing method.

This PDF is instructional for running fuel rail pressure tests on Jeep MPI. This is the 1997-up XJ Cherokee and TJ Wrangler type with fuel tank mounted pressure regulator and single-rail injection.

In the late '90s, my engineer friends, Jeep performance enthusiasts at Mopar, were talking about 5.9L Mopar V-8 injectors for 4.0L/4.6L stroker engine builds. This has apparently been a route to go, with a 24-pound/hour injector rating.

I researched the Jeep ZJ Grand Cherokee 5.2L/5.9L V-8 injectors from the mid-‘90s: 1995 Jeep 5.2 ZJ/Dodge 5.9L V-8 injectors are Part #53030262 and rated to flow 24.6-pound/hour at 39 PSI. By 1996, the Jeep V-8 injectors rated 23.2 pounds at 49 PSI. The 1995 Mopar injectors (24.6#/hour @ 39 PSI) could be an alternative to the 302 Ford injectors for a stroker build in a 1991-95 Jeep 4.0L MPI chassis application if the engine demands that kind of flow.

Summing it up, if GB is accurate, using the right injector cores and parts for this application, HESCO is marketing a “24-pound/hour @ 43.5 PSI injector for a stroker inline six. A caution here is that the '97-up Jeep TJ Wrangler and XJ Cherokee have a 49.2 +/- 5 PSI rail pressure. Flow could be higher than 24 pounds/hour at this 49.2 +/- 5 PSI rail pressure.

If the GB812-12132 injector is okay for a coil pack later engine with the later cylinder head casting, the GB812-12132 square plug injector would be the choice for later coil-pack engines. There are a number of sources for these GB injectors.

We're still testing the CompCams 252H camshaft in a later 4.0L (1999-up TJ Wrangler/2000-up XJ Cherokee) engine with the redesigned head and coil pack ignition. Tony and I will update on these late 4.0L/stroker engines. The pre-'99 stroker engines and stock PCMs have worked well with this camshaft grind. We're consulting with CompCams about a possible new grind for later coil-pack ignition stroker engines.The 1997-up TJ Wrangler and Cherokees with the tank-mounted fuel regulator use higher fuel pump/line pressure. I would stick with Mopar 53030262 or Ford 302 V-8 type injectors* on the 1997-98 TJ Wranglers and Cherokees through 1999 (without the coil pack system).